Rubber treating apparatus



Aug. 17, 1937. A. H. CLAESSEN RUBBER TREATING APPARATUS Filed March 13, 1936 A/A/E Justin/firm U/adsen ATTORNEY Patented Aug. 17, 1937 UNITED STATES RUBBER TREATING APPARATUS Austin Horace Glaessen, Kuala Lumpur, Selangor, Federated Malay States Application March 13, 1936, Serial No. 68,732

4 Claims.

This invention relates to rubber treating apparatus and has for an object to provide a novel form of treating medium for supplying heat uniformly throughout the superficial area of the 5 article to be treated.

A further object is to provide the closed spaces of rubber treating apparatus with a fusible alloy of tin, lead, cadmium and bismuth, or pure tin or pure lead according to the degree of heat needed, and reducing this alloy to a molten state by means of an electric resistance element whereby a higher degree of efficiency of heat application to the articles to be treated will be obtained, and the troublesome annoyances of steam control will be eliminated.

Vulcanization of rubber is usually accomplished either in a steam bath or by plates internally heated by steam. Steam under pressure has a ratio, in temperature, parallel with the pressure per square inch. A rise in pressure is equivalent to a rise in temperature. Ordinarily steam confined in rubber treating containers is under thirty to sixty pounds pressure per square inch which is equivalent to a temperature range of from 275 5 degrees F. to 307 degrees F.

The objection to the use of steam as a heating medium is that steam must be confined in pressure-tight chambers. This necessitates massive structures and elaborate means for keeping these chambers steam tight. The constantcooling of steam, conducted through great lengths of piping to each machine, is another undesirable feature.

Another objection to the use of steam is the impracticability of simultaneously obtaining various pressures at each machine from one common steam source.

In the present invention the use of steam as a medium of heat transfer is dispensed with, and in its place, a metallic alloy brought to a fluid state and maintained at the required temperature electrically, is used in the vulcanizers, mixing mills, proofing and spreading machines, and other apparatus employed in the vulcanizing, the masticating and other heat treatment of rubber.

46 With the above and other objects in view the invention consists of certain novel details of construction and combinations of parts hereinafter fully described and claimed, it being understood that various modifications may be resorted to 50 within the scope of the appended claims without departing from the spirit or sacrificing any of the advantages of the invention In the accompanying drawing forming part of this specification,

Fizurelisacrosssectional 'viewofapparatus suitable for the purpose of vulcanizing a rubber article such as a tube.

Figure 2 is a front elevation of one of the electrical resistance elements.

Figure 3 is an enlarged detail sectional view 5 of a portion of the resistance elements shown in Figure 2.

Referring now to thedrawing in which like characters of reference designate similar parts in the various views, there is shown in Figure 1 a. 10 vulcanizing bath of rectangular form suitable for treating long articles such as inner tubes In. In this embodiment of the invention the tube is supported upon a core I i and is pressed against the core by means of a two-piece mold l 2, the sections of which are clamped together by bolts [3. The tube within its mold is enveloped by a chamber [4, the walls of which may be formed of earthenware, metal plates, or cast metal, as

desired. The chamber is filled with a fusible 20 alloy l5, hereinafter more fully described, which forms the heat treating medium.

Electrical resistance elements "5 are mounted on the top, bottom and side walls of the chamber and the resistance elements are connected by cir- 25 cuit wires II and I8 to current supply circuit wires 19 and 20. A rheostat 2| controls the supply of current from the supply circuit to the resistance elements, and a switch 22 permits the current being supplied to the elements at the be- 30 ginning of the vulcanizing process and cut off from the elements when the process is completed.

The fusible alloy I5 is preferably one which can be made to melt in hot water, that is, one which I has a melting point at or below that of boiling water. One example of such an alloy is composed of tin, one part, lead, two parts, cadmium, two parts, and bismuth, four parts, and has a. melting point at about degrees F. Another 40 suitable alloy is tin, three parts, lead, five parts, and bismuth, eight parts, having a melting point at about 202 degrees F. a

The resistance element preferably comprises a. helical nickel chrome wire 23 imbedded in an insulating powder 24, magnesium oxide, for example, packed tightly in a sheathing 25 of metal capable of being easily heated and not easily damaged by high temperatures.

Preferably each heating element I8 is in the form of contiguous reversed loops of identical dimensions, as shown in Figure 2. These elements are arranged in rows throughout the entire inner surface area of the chamber so that heat transference from the elements to the fusible alloy will 55 be substantially uniform: throughout the entire mass of the alloy, which latter in turn will distribute a uniform temperature throughout the entire area of the .metal member used for vulcanizing,

5 in this instance the mold l2.

Although I have described the use of a fusible alloyreduced to'aliquid state by the agency of heat, as a vulcanizing bath by which compounded rubber goods maybe cured by emersion, the scope of the invention is intended to extend to the use of the same within the cavity, internal chambers and other spaces of apparatus used for thevulcanization of rubber, and also to the use of the same for the softening of com-pounded l5 rubber for spreading on fabric and to the use of .the same in the chambers of mixing rolls used for the mastication or compounding of rubber.

In practice, the alloy either before or after being reduced to a liquid state, may be placed 20 within enclosed chambers such as the hollow rolls of a calendering machine or of a mixing mill. These chambers are provided with electrical heating elements of the resistance type for maintaining the alloy in a fluid state. The desired 26 degree of heat can be arrived at first by selectiiig the alloy or pure metal best suited to the minimum degree of heat required, and then adjusting the temperature by means of a sua'table regulating device for increasing or diminishing the supply of current from the current source.

From. the above description it is thought that the construction and operation of the invention .will be fully understood without further explanation. 3 What is claimed is:

1. Apparatus for vulcanizing rubber comprising a chamber, means for supporting the article to bevulcanized entirely within the chamber, electric heating coils extending upon the entire inner surface area of the chamber, means for supplying electric current to the coils, and a fusible metal alloy in the chamber adapted to diffuse the heat of the coils throughout the entire interior of the chamber, the reduction of the alloy to the fluid state being utilized to auto-' matically envelope the article to be vulcanized.

2. Apparatus for vulcanizing rubber comprising a chamber, means for supporting the article to be vulcanized entirely within the chamber,

heating coils extending upon the entire inner surface of the chamber, metal sheathings for the coils adapted to be easily heated and not easily l0 damaged by high temperatures, an insulating powder packed tightly in the sheathings, means for supplying electric current to the coils, and a fusible metal alloy in the chamber adapted to contact with the article to be vulcanized and with the sheathings and evenly diffuse heat from the coils uniformly throughout the entire surface of the article.

3. Apparatus for vulcanizing rubber comprising a chamber, a fusible metal alloy in the. chamber, electric heating coils in the chamber insu-' lated against short-circuiting, means for supplying current to the coils and controlling the same so that heat passing from the coils can melt the alloy and maintain it at any desired temperature while the fluid state of the alloy is utilized as a hot bath into which the article to be vulcanized can be submerged, and means for supporting the article to be vulcanized entirely within the chamber.

4. Apparatus for vulcanizing rubber comprising a chamber, a fusible metal alloy in the cham-- ber, heating coils in the chamber, means for supplying current to the coils and controlling the current, means for holding and molding the article to be vulcanized consisting of a core to support the rubber, an outer mold adapted to shape and press the rubber, and anchoring means for maintaining the mold centrally in position in relation to the alloy and entirely Within the chamher.

AUSTIN H. CLAESSEN. 

